US20150041953A1

US20150041953A1 - Semiconductor component and method of manufacture

Info

Publication number: US20150041953A1
Application number: US14/341,377
Authority: US
Inventors: Yupeng CHEN; Rong Liu; Phillip Holland; Umesh Sharma; Ralph Wall
Original assignee: Semiconductor Components Industries LLC
Current assignee: Semiconductor Components Industries LLC
Priority date: 2013-08-09
Filing date: 2014-07-25
Publication date: 2015-02-12
Anticipated expiration: 2034-07-25
Also published as: DE202014103705U1; CN204230240U; US9111758B2

Abstract

In accordance with an embodiment, a semiconductor component includes a common mode filter monolithically integrated with a protection device. The common mode filter may be composed of first, second, third, and fourth coils, wherein each coil has first and second terminals and the first coil is magnetically coupled to the second coil and the third coil is magnetically coupled to the fourth coil. The protection device has a first terminal coupled to the first terminal of the first coil and a second terminal coupled to the first terminal of the third coil. An energy storage element has a terminal coupled to the second and first terminals of the first and second coils, respectively. Another embodiment includes monolithically integrating a common mode filter with a protection device and monolithically integrating a metal-insulator-metal capacitor with the common mode filter.

Description

TECHNICAL FIELD

The present invention relates, in general, to semiconductor components and, more particularly, to signal transmission in semiconductor components.

BACKGROUND

Transmission protocols within communications systems may include the use of single-ended signals, differential signals, or combinations of single-ended and differential signals. For example, single-ended signals and differential signals are suitable for use in portable communications systems that employ low speed data transmission. However, in communications systems that employ high speed data transmission, it is desirable to use differential signals because of their noise immunity properties. These types of systems include mobile electronic devices such as, for example, smartphones, tablets, computers, and systems that include Universal Serial Bus (USB) applications. In addition to noise immunity, it is desirable to include protection from large transient voltage and current spikes, which can damage these systems. Typically, noise filters, also known as Common Mode Filters (CMF) and Electro-Static Discharge (ESD) protection circuits are mounted to a Printed Circuit Board (PCB) along with other circuitry of the communications system to reduce common mode noise on differential signal lines and to suppress large transient electrical spikes, respectively. This configuration of elements occupies a large area on a PCB, which is disadvantageous in mobile electronic devices. The ESD protection circuits are fabricated from low resistivity substrates to accommodate high currents encountered during ESD events. It is undesirable to manufacture filter elements such as inductor coils on a low resistivity substrate because of the presence of eddy currents which degrade filter performance.
Accordingly, it would be advantageous to have a structure and method for manufacturing a semiconductor component that provides protection from large electrical transients and provides noise filtering. It would be of further advantage for the structure and method to be cost efficient to implement.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood from a reading of the following detailed description, taken in conjunction with the accompanying drawing figures, in which like reference characters designate like elements and in which:

FIG. 1 is a circuit schematic of a semiconductor component in accordance with an embodiment of the present invention;

FIG. 2 is a circuit schematic of a semiconductor component in accordance with another embodiment of the present invention;

FIG. 3 is a top view of a layout of a semiconductor component in accordance with an embodiment of the present invention;

FIG. 4 is a plot of the common mode performance of a semiconductor component in accordance with an embodiment of the present invention;

FIG. 5 is a plot of the differential mode performance of a semiconductor component in accordance with an embodiment of the present invention;

FIG. 6 is a plot of the ElectroStatic Discharge clamping performance in a positive direction of a semiconductor component in accordance with an embodiment of the present invention;

FIG. 7 is a plot of the ElectroStatic Discharge clamping performance in a negative direction of a semiconductor component in accordance with an embodiment of the present invention;

FIG. 8 is a cross-sectional view of a semiconductor component at an early stage of manufacture in accordance with an embodiment of the present invention;

FIG. 9 is a cross-sectional view of the semiconductor component of FIG. 8 at a later stage of manufacture;

FIG. 10 is a cross-sectional view of the semiconductor component of FIG. 9 at a later stage of manufacture;

FIG. 11 is a cross-sectional view of the semiconductor component of FIG. 10 at a later stage of manufacture;

FIG. 12 is a is a cross-sectional view of the semiconductor component of FIG. 11 at a later stage of manufacture;

FIG. 13 is a cross-sectional view of the semiconductor component of FIG. 12 at a later stage of manufacture;

FIG. 14 is a cross-sectional view of the semiconductor component of FIG. 13 at a later stage of manufacture;

FIG. 15 is a cross-sectional view of the semiconductor component of FIG. 14 at a later stage of manufacture;

FIG. 16 is a cross-sectional view of the semiconductor component of FIG. 15 at a later stage of manufacture;

FIG. 17 is a cross-sectional view of the semiconductor component of FIG. 16 at a later stage of manufacture;

FIG. 18 is a cross-sectional view of the semiconductor component of FIG. 17 at a later stage of manufacture;

FIG. 19 is a top view of a coil pattern for use in manufacturing the semiconductor component of FIG. 18;

FIG. 20 is a cross-sectional view of the semiconductor component of FIG. 18 at a later stage of manufacture;

FIG. 21 is a cross-sectional view of the semiconductor component of FIG. 20 at a later stage of manufacture;

FIG. 22 is a cross-sectional view of the semiconductor component of FIG. 21 at a later stage of manufacture;

FIG. 23 is a top view of a coil pattern for use in manufacturing the semiconductor component of FIG. 20;

FIG. 24 is a cross-sectional view of the semiconductor component of FIG. 22 at a later stage of manufacture;

FIG. 25 is a circuit schematic of a semiconductor component in accordance with another embodiment of the present invention;

FIG. 26 is a circuit schematic of a semiconductor component in accordance with another embodiment of the present invention;

FIG. 27 is a circuit schematic of a semiconductor component in accordance with another embodiment of the present invention;

FIG. 28 is a circuit schematic of a semiconductor component in accordance with another embodiment of the present invention;

FIG. 29 is a top view of a layout of a semiconductor component in accordance with another embodiment of the present invention;

FIG. 30 plot of the common mode and differential mode performance of a semiconductor component in accordance with an embodiment of the present invention;

FIG. 31 is a plot of the ElectroStatic Discharge clamping performance in a positive direction of a semiconductor component in accordance with an embodiment of the present invention; and

FIG. 32 is a plot of the ElectroStatic Discharge clamping performance in a negative direction of a semiconductor component in accordance with an embodiment of the present invention.

For simplicity and clarity of illustration, elements in the figures are not necessarily to scale, and the same reference characters in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current flow through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain n-channel or p-channel devices, or certain n-type or p-type doped regions, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with embodiments of the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action. The use of the words approximately, about, or substantially means that a value of an element has a parameter that is expected to be very close to a stated value or position. However, as is well known in the art there are always minor variances that prevent the values or positions from being exactly as stated. It is well established in the art that variances of up to about ten percent (10%) (and up to twenty percent (20%) for semiconductor doping concentrations) are regarded as reasonable variances from the ideal goal of exactly as described.

DETAILED DESCRIPTION

Generally, the present invention provides a semiconductor component comprising a common mode filter monolithically integrated with a protection device and a method for manufacturing the semiconductor component wherein the common mode filter comprises a first coil having first and second terminals; a second coil having first and second terminals, the first terminal of the second coil coupled to the second terminal of the first coil, the first coil magnetically coupled to the second coil; a third coil having first and second terminals; a fourth coil having first and second terminals, the first terminal of the fourth coil coupled to the second terminal of the third coil, the third coil magnetically coupled to the fourth coil; the protection device having a first terminal coupled to the first terminal of the first coil and a second terminal coupled to the first terminal of the third coil; and a first energy storage element having first and second terminals, the first terminal of the first energy storage element coupled to the second and first terminals of the first and second coils, respectively.
In accordance with another embodiment, the semiconductor component further includes a second energy storage element having first and second terminals, the first terminal of the second energy storage element coupled to the second and first terminals of the third and fourth coils, respectively, and the second terminals of the first and second energy storage elements coupled together.
In accordance with another embodiment, wherein the first and second energy storage elements are metal-insulator-metal capacitors.
In accordance with another embodiment, the semiconductor component further includes a fifth coil, the fifth coil having first and second terminals, the first terminal coupled to the second terminals of the first and second energy storage elements.
In accordance with another embodiment, the semiconductor component further includes a third energy storage element having a first terminal coupled to the first terminal of the fifth coil and a second terminal coupled to the second terminal of the fifth coil.
In accordance with another embodiment, the protection device comprises the protection device comprises a first diode having an anode and a cathode, the cathode coupled to the first terminal of the first coil and a second diode having an anode and a cathode, the anodes of the first and second diodes coupled together and the cathode of the second diode coupled to the first terminal of the third coil.
In accordance with another embodiment, the protection device comprises a first diode having an anode and a cathode and a second diode having an anode and a cathode, the cathode of the first diode coupled to the first terminal of the first coil, the cathode of the second diode coupled to the anode of the first diode and the anode of the second diode coupled to the first terminal of the third coil.
In accordance with another embodiment, the semiconductor component further includes a transistor having a control electrode and first and second current carrying electrodes, the first current carrying electrode coupled to the cathode of the first diode and the second current carrying electrode coupled to the anode of the second diode.
In accordance with another embodiment, method for manufacturing a semiconductor component having a common mode filter monolithically integrated with a protection device is provided, wherein the method comprises providing a semiconductor material having a major surface and a resistivity of at least 10 ohm-centimeters; forming a plurality of trenches in the semiconductor material; forming the protection device from the semiconductor material between first and second trenches of the plurality of trenches; monolithically integrating a common mode filter with the protection device; and monolithically integrating a metal-insulator-metal capacitor with the common mode filter.
In accordance with another embodiment, providing the semiconductor material comprises: providing a semiconductor substrate having a resistivity of at least 5 ohm-centimeters; forming a first epitaxial layer of a first conductivity type over the semiconductor substrate; and forming a second epitaxial layer of a second conductivity type over the first epitaxial layer.
In accordance with another embodiment, the method further includes including forming a buried layer of the first conductivity type from portions of the first and second epitaxial layers.
In accordance with another embodiment, forming the plurality of trenches includes forming at least first, second, third, and fourth trenches, wherein a portion of the semiconductor material between the first and second trenches serves as a first device region, a portion of the semiconductor material between the second and third trenches serves as a second device region, and a portion of the semiconductor material between the third and fourth trenches serves as a third device region.
In accordance with another embodiment, the method further includes forming a first diode from the first device region, a second diode from the second device region, and a transistor from the third device region.
In accordance with another embodiment, the method further includes forming a first and second dopant regions of the second conductivity type in the third device region; forming third and fourth dopant regions of the second conductivity type in the first and second dopant regions and fifth and sixth dopant regions of the second conductivity type in the first and second device regions, respectively; and forming seventh and eighth dopant regions of the first conductivity type in the first and second device regions, respectively.
In accordance with another embodiment, the method further includes forming a first dielectric layer over the semiconductor material, the first dielectric layer configured to magnetically decouple the common mode filter from the protection structure; forming a first coil of the common mode filter over the first dielectric layer; forming a second dielectric layer over the first coil and the first dielectric layer; and forming a second coil over the second dielectric layer, the second dielectric layer configured to magnetically coupled the first coil and the second coil.
In accordance with another embodiment, the method further includes forming a third layer of dielectric material over the second coil and the second layer of dielectric material.
In accordance with another embodiment, the first, second, and third layers of dielectric material are photosensitive polyimides.
In accordance with another embodiment, the monolithically integrating the metal-insulator-metal capacitor comprises: forming a first layer of dielectric material over the semiconductor material; forming a first layer of electrically conductive material over the first layer of dielectric material; forming a second layer of dielectric material over first layer of electrically conductive material; and forming a second layer of electrically conductive material over the second layer of dielectric material.
In accordance with another embodiment, a semiconductor component that includes a common mode filter monolithically integrated with a protection device comprises: a semiconductor material having a peripheral region, a central region, and a resistivity of at least 5 ohm-centimeters, wherein the central region comprises a plurality of device regions isolated by isolation trenches; a first coil over a first portion of the central region; a second coil over a second portion of the central region; a first insulating material over the first and second coils; a third coil over the first portion of the central region; a fourth coil over the second portion of the central region, the first insulating material between the first and third coils and the second and fourth coils; a fifth coil over the peripheral region; a protection device monolithically integrated with the first, second, third, fourth, and fifth coils, the protection device having a first terminal coupled to the first coil and a second terminal coupled to the second coil; and a first metal-insulator-metal capacitor monolithically integrated with the protection device and over the first portion of the central region.
In accordance with another embodiment, the semiconductor component further includes second metal-insulator-metal capacitor over the second portion of the central region, wherein the first metal-insulator-metal capacitor is laterally surrounded by the first coil and the second metal-insulator-metal capacitor is laterally surrounded by the second coil.
FIG. 1 is a circuit diagram of a semiconductor component 10 that includes a common mode filter 12 monolithically integrated with a protection device 14 and a notch adjustment element 16. What is shown in FIG. 1 is a T-coil filter 18 connected to a filter capacitor 20 and a T-coil filter 22 connected to a filter capacitor 24. T-coil filter 18 is comprised of an inductor 18A having input and output terminals and an inductor 18B comprising input and output terminals. The input terminal of inductor 18A is coupled to or, alternatively, serves as a non-inverting differential input of common mode filter 12. The output terminal of inductor 18A is connected to the input terminal of inductor 18B and the output terminal of inductor 18B is connected to or, alternatively, serves as a non-inverting differential output of common mode filter 12. Filtering capacitor 20 has a pair of terminals wherein one of the terminals is commonly connected to the output terminal of inductor 18A and to the input terminal of inductor 18B. T-coil filter 22 is comprised of an inductor 22A having input and output terminals and an inductor 22B having input and output terminals. The input terminal of inductor 22A is coupled to or, alternatively, serves as an inverting differential input of common mode filter 12. The output terminal of inductor 22A is connected to the input terminal of inductor 22B and the output terminal of inductor 22B is connected to or, alternatively, serves as an inverting differential output of common mode filter 12. Filtering capacitor 24 has a pair of terminals wherein one of the terminals is commonly connected to the output terminal of inductor 22A and to the input terminal of inductor 22B. The other terminals of capacitors 20 and 24 are commonly connected together.
In accordance with an embodiment, notch adjustment element 16 comprises an inductor 26 in parallel with a filter capacitor 28. Inductor 26 and filter capacitor 28 each have a terminal commonly connected together and to the commonly connected terminals of filter capacitors 20 and 24. In addition, inductor 26 and filter capacitor 28 each have terminals commonly connected together for receiving a source of operating potential. By way of example, the source of operating potential is ground. Inductor 26 may be referred to as a tail inductor and capacitor 28 may be referred to as a tail capacitor.
Protection device 14 has a terminal connected to the input terminal of inductor 18A, a terminal connected to the input terminal of inductor 22A, and a terminal that may be coupled for receiving a source of potential. By way of example, the source of potential is ground. In accordance with an embodiment, protection device 14 is an electrostatic discharge protection device comprising diodes 30 and 32. Diode 30 has a cathode connected to the non-inverting input of common mode filter 12 and an anode connected to the anode of diode 32, which diode 32 has a cathode connected to the inverting input of common mode filter 12.
FIG. 2 is a circuit diagram of a semiconductor component 10A that includes a common mode filter 12 monolithically integrated with a protection device 14A and a notch adjustment element 16. Common mode filter 12 and notch adjustment element 16 have been described with reference to FIG. 1. Like protection device 14, protection device 14A may be an electrostatic protection device. It should be noted that reference character A has been appended to reference characters 10 and 14 in FIG. 2 to distinguish between semiconductor component 10 and protection device 14 of FIG. 1.
Protection device 14A comprises single channel ESD structures 40 and 42. ESD structure 40 comprises diodes 44 and 46 and an npn bipolar transistor 48 and ESD structure 42 comprises diodes 50 and 52 and an npn bipolar transistor 54. Diode 44 has an anode commonly connected to the cathode of diode 46 and to the non-inverting input of common mode filter 12. The collector of npn bipolar transistor 48 is connected to the cathode of diode 44 and the emitter of npn bipolar transistor 48 is connected to the anodes of diodes 46 and 50. Diode 52 has an anode commonly connected to the cathode of diode 50 and to the non-inverting input of common mode filter 12. The collector of npn bipolar transistor 54 is connected to the cathode of diode 52 and the emitter of npn bipolar transistor 54 is connected to the anodes of diodes 46 and 50.
FIG. 3 is a layout 60 of T-coil filters such as, for example, T- coil filters 18A, 18B, 22A, and 22B. What is show in FIG. 3 are coils such as, for example, coils 18A and 18B and coil 26. Coils 18A, 18B, 22A, 22B, and 26 are manufactured over a semiconductor material having a central portion and a peripheral portion. Coils 18A and 18B are formed over a sub-portion of the central portion of the semiconductor material and coils 22A and 22B are formed over another sub-portion of the central portion of the semiconductor material. Capacitor 20 is laterally bounded by coils 18A and 18B and capacitor 24 is laterally bounded by coils 22A and 22B. Coil 26 is formed over a peripheral portion and surrounds coils 18A, 18B, 22A, and 22B. It should be noted that coils 18A and 18B are configured to be vertically positioned with respect to each other and vertically spaced apart by a dielectric material and coils 22A and 22B are configured to be vertically positioned with respect to each other and vertically spaced apart by a dielectric material.
FIG. 4 is a plot 80 of the common mode performance of a semiconductor component in accordance with embodiments of the present invention. Plot 80 shows the common mode gain versus frequency response and includes notches 82, 84, and 86. Inductors 18A and 16 in combination with capacitor 20 tune or set the frequency of notch 82, inductors 18A and 22A in combination with capacitors 20 and 24 tune or set the frequency of notch 84, and inductor 16 and capacitor 20 tune or set the frequency of notch 86.
FIG. 5 is a plot 85 of the differential mode performance of a semiconductor component in accordance with an embodiment of the present invention, where plot 85 shows the differential mode gain versus frequency.
FIG. 6 is a plot 90 of ESD clamping performance of a semiconductor component in accordance with embodiments of the present invention in which an ESD event is in the positive direction.
FIG. 7 is a plot 95 of ESD clamping performance of a semiconductor component in accordance with embodiments of the present invention in which an ESD event is in the negative direction.
FIG. 8 is a cross-sectional view of a portion of a semiconductor component 100 such as, for example, a common mode filter monolithically integrated with Electrostatic Discharge (ESD) protection devices and a Metal-Insulator-Metal (MIM) capacitor, during manufacture in accordance with an embodiment of the present invention. What is shown in FIG. 8 is a semiconductor material 102 having opposing surfaces 104 and 106. Surface 104 is also referred to as a front or top surface and surface 106 is also referred to as a bottom or back surface. In accordance with this embodiment, semiconductor material 102 comprises a semiconductor substrate 108 doped with an impurity material of p-type conductivity and having a resistivity of at least about 100 Ohm-centimeter (Ω-cm). Preferably, the resistivity of substrate 108 is 100 Ω-cm. More preferably, the resistivity of substrate 108 is 500 Ω-cm or more, and even more preferably the resistivity of substrate 108 is 1,000 Ω-cm or more. Suitable materials for substrate 108 include silicon and compound semiconductor materials such as, for example, gallium nitride, gallium arsenide, indium phosphide, Group III-V semiconductor materials, Group II-VI semiconductor materials, or the like.
In accordance with an embodiment, semiconductor material 102 further comprises an epitaxial layer 110 of n-type conductivity formed on high resistivity substrate 108 and an epitaxial layer 112 of p-type conductivity formed on epitaxial layer 110. A buried layer 114 is formed in a portion of epitaxial layers 110 and 112.
It should be noted that a region or layer doped with an n-type dopant or impurity material is said to be of an n-type conductivity or an n conductivity type and a region or layer doped with a p-type dopant or impurity material is said to be of a p-type conductivity or a p conductivity type.
A layer of dielectric material 118 is formed on or from semiconductor material 102. In accordance with an embodiment, the material of dielectric layer 118 is silicon dioxide having a thickness ranging from about 1,000 Angstroms (Å) to about 10,000 Å. Techniques for forming silicon dioxide layer 118 are known to those skilled in the art. For example, dielectric layer 118 may be formed by oxidizing semiconductor material 102 or it may be a TEOS layer formed using plasma enhanced chemical vapor deposition. Still referring to FIG. 8, a layer of photoresist is patterned over dielectric layer 118 to form a masking structure 120 having masking elements 122 and openings 124 that expose portions of dielectric layer 118.
Referring now to FIG. 9, the portions of dielectric layer 118 unprotected by masking elements 122 are removed using a wet etch that selectively etches the material of dielectric layer 118. Trenches 126 are formed through the portions semiconductor material 102 that are exposed by the removal of the portions of dielectric layer 118. In accordance with an embodiment, trenches 126 extend from surface 104 through epitaxial layer 112, buried layer 114, epitaxial layer 110 and into semiconductor substrate 108. Alternatively, trenches 126 terminate before reaching semiconductor substrate 108. Trenches 126 create epitaxial regions 112A, 112B, 112C, and 112D from epitaxial layer 112, epitaxial regions 110A, 110B, 110C, and 110D from epitaxial layer 110, and buried layer regions 114A, 114B, and 114C from epitaxial layer 114.
Still referring to FIG. 9, masking elements 122 and any oxide including dielectric layer 118 are removed and a dielectric layer 128 is formed on the exposed portions of epitaxial layer 112 including epitaxial regions 112A, 112B, 112C, and 112D and on trenches 126. By way of example dielectric layer 128 is oxide having a thickness ranging from 150 Å to about 400 Å, which oxide may be referred to as a pad oxide. It should be noted that a pad oxide may be referred to as a screen oxide. A layer of photoresist is patterned over dielectric layer 128 to form a masking structure 130 having masking elements 132 and openings 134 that expose portions of dielectric layer 128 over epitaxial region 112C.
P- type dopant regions 140 and 142 are formed in epitaxial region 112C by implanting an impurity material of p-type conductivity through the exposed portions of dielectric layer 128 and into epitaxial region 112C. P- type dopant regions 140 and 142 may be formed by implanting the impurity material into epitaxial region 112C at a dose ranging from about 5×10¹²atoms per square centimeter (atoms/cm²) to about 1×10¹⁴atoms/cm²and an implant energy ranging from about 25 kilo-electronVolts (keV) to about 50 keV.
Referring now to FIG. 10, masking elements 132 are removed and the p-type dopant or impurity materials are driven into epitaxial region 112C by placing semiconductor material 102 in an inert ambient environment at a temperature ranging from about 1,000° C. to about 1,250° C. for a time ranging from about 2.5 hours to about 3.5 hours. By way of example, p- type dopant regions 140 and 142 are formed by implanting the p-type impurity material at a dose of about 2×10¹³atoms/cm²and an implant energy of about 35 keV and driving the dopant into semiconductor material 102 for about 3 hours in a nitrogen ambient environment at a temperature of about 1,150° C. Suitable p-type dopants or impurity materials include boron, indium, or the like. It should be noted that p- type dopant regions 140 and 142 are within epitaxial region 112C and that they are laterally spaced apart from each other.
Still referring to FIG. 10, a layer of photoresist is patterned over dielectric layer 128 to form a masking structure 144 having masking elements 146 and openings 148 that expose portions of dielectric layer 128 over epitaxial regions 112A, 112B, and 112C. An n-type dopant region 150 is formed in epitaxial region 112A, an n-type dopant region 152 is formed in epitaxial region 112B, and n- type dopant regions 154 and 156 are formed in p- type dopant regions 140 and 142, respectively, by implanting an impurity material of n-type conductivity through dielectric layer 128 and into epitaxial regions 112A, 112B, and 112C. N- type dopant regions 150, 152, 154, and 156 may be formed by implanting the impurity material through the exposed portions of dielectric layer 128 and into epitaxial regions 112A, 112B, and 112C at a dose ranging from about 5×10¹²atoms/cm²to about 1×10¹⁴atoms/cm²and an implant energy ranging from about 25 keV to about 50 keV.
Referring now to FIG. 11, masking elements 146 are removed and a layer of photoresist is patterned over dielectric layer 128 to form a masking structure 160 having masking elements 162 and openings 163 that expose portions of dielectric layer 128 over epitaxial regions 112A and 112B. A p-type dopant region 164 is formed in epitaxial region 112A and a p-type dopant region 166 is formed in epitaxial region 112B by implanting an impurity material of p-type conductivity through the exposed portions of dielectric layer 128 and into epitaxial regions 112A and 112B. P- type dopant regions 164 and 166 may be formed by implanting the impurity material into epitaxial regions 112A and 112B at a dose ranging from about 5×10¹²atoms/cm²to about 1×10¹⁴atoms/cm²and an implant energy ranging from about 25 keV to about 40 keV. By way of example, p- type dopant regions 164 and 166 are formed by implanting the p-type impurity material at a dose of 2×10¹³atoms/cm²and an implant energy of about 35 keV and driving the dopant into epitaxial regions 112A and 112B for about 3 hours in a nitrogen ambient environment at a temperature of about 1,150° C. Driving in the impurity material also anneals semiconductor material 102. Suitable p-type dopants or impurity materials include boron, indium, or the like. It should be noted that p- type dopant regions 164 and 166 are laterally spaced apart from n- type dopant regions 150 and 152, respectively.
Referring now to FIG. 12, masking elements 162 are removed and any dielectric material including dielectric layer 128 are removed and a layer of dielectric material 168 is formed on semiconductor substrate 102 and over trenches 126. A layer of dielectric material 170 is formed on dielectric layer 168 and a layer of dielectric material 172 is formed on dielectric layer 168. Dielectric layer 168 may be formed by oxidation and has a thickness ranging from about 100 Å to about 500 Å, dielectric layer 170 may be an undoped silicon glass formed by plasma enhanced chemical vapor deposition and has a thickness ranging from about 1,000 Å to about 3,000 Å, and dielectric layer 172 may be borophosphosilicate glass formed by plasma enhanced chemical vapor deposition and has a thickness ranging from about 5,000 Å to about 10,000 Å. By way of example, dielectric layer 168 has a thickness of about 140 Å, dielectric layer 170 has a thickness of about 1,300 Å, and dielectric layer 172 has a thickness of about 6,000 Å. A reflow cycle is performed at a temperature ranging from about 900° C. to about 1,000° C. to planarize dielectric layer 172 and to activate the dopants of dopant regions 150, 152, 154, 156, 164, and 166. By way of example, the reflow cycle is at about 950° C. It should be noted that the thicknesses and methods of forming dielectric layers 168, 170, and 172 are not limitations of the present invention.
Still referring to FIG. 12, a layer of photoresist is patterned over dielectric layer 172 to form a masking structure 174 having masking elements 176 and openings 178 that expose portions of dielectric layer 172.
Referring now to FIG. 13, the portions of dielectric layer 172 exposed by openings 178 and the portions of dielectric layers 170 and 168 unprotected by masking elements 176 are removed using, for example, a wet etch technique. Removing the portions of dielectric layers 172, 170, and 168 exposes portions of dopant regions 150, 152, 154, 156, 164, and 166. Masking elements 176 are removed and a layer of refractory metal (not shown) is deposited over dielectric layer 172 and the exposed portions of dopant regions 150, 152, 154, 156, 164, and 166. By way of example, the refractory metal is titanium having a thickness ranging from about 100 Å to about 1,000 Å. A rapid thermal anneal is performed wherein the refractory metal is heated to a temperature ranging from about 500° C. to about 700° C. The heat treatment causes the titanium to react with the silicon to form titanium silicide in all regions in which the titanium is in contact with silicon or polysilicon. Alternatively, the refractory metal can be titanium nitride, tungsten, cobalt, or the like. The silicide formed by the rapid thermal anneal serves as a barrier layer.
Referring now to FIG. 14, a barrier metal layer 179 may be formed over dielectric layer 172 and the exposed portions of dopant regions 150, 152, 154, 156, 164, and 166. It should be noted that barrier metal layer 179 may be comprised of a plurality of metal layers, however they are shown as a single layer for the sake of clarity. A layer of aluminum copper (AlCu) 180 is formed over the barrier metal layer 179. By way of example, aluminum copper layer 180 is sputtered onto barrier metal layer 179 and has a thickness ranging from about 1 micrometer (μm) to about 4 μm. Alternatively, layer 180 may be aluminum, aluminum copper, aluminum copper silicon, aluminum silicon, or the like. A layer of photoresist is patterned over aluminum copper layer 180 to form a masking structure 182 having masking elements 184 and openings 186 that expose portions of aluminum copper layer 180.
Referring now to FIG. 15, the exposed portions of aluminum copper layer 180 are removed using a metal etching process and leaves contacts 190, 192, 194, and 196, and a conductor 198. Layer 180 may be etched using a plasma etch or a wet etch. Contact 190 serves as an anode contact for a diode 191 and contact 192 serves as a cathode contact for diode 191 and an anode contact for a diode 193, contact 194 serves as an anode contact for diode 193 and as a collector contact for a bipolar transistor 197, and contact 196 serves as an emitter contact of bipolar transistor 197. It should be noted that dopant region 164 forms the anode of diode 191, dopant region 150 forms the cathode of diode 191, dopant region 166 forms the anode of diode 193, dopant region 152 forms the cathode of diode 193, dopant region 154 forms the collector of bipolar transistor 197, and dopant region 156 forms the emitter of bipolar transistor 197. Contacts 190 and 192 may serve as connection contacts to make connections between the common mode filter and other circuit elements. Conductor 198 forms a plate of a metal-insulator-metal capacitor.
Still referring to FIG. 15, a passivation layer 200 is formed on electrodes 190-196, conductor 198, and on the exposed portions of dielectric layer 172. By way of example, passivation layer 200 comprises a layer of silicon nitride having a thickness of about 7 kÅ. Alternatively, passivation layer 200 may be comprised of another suitable dielectric material or multiple layers of dielectric material. A layer of photoresist is patterned over passivation layer 200 to form a masking structure 202 having masking elements 204 and an opening 206 that exposes a portion of passivation layer 200.
Referring now to FIG. 16, the portion of passivation layer 200 exposed by opening 206 may be removed using, for example, a wet etch technique. Removing the exposed portion of passivation layer 200 exposes conductor 198. Masking elements 204 are removed and a layer of dielectric material 208 having a thickness ranging from about 100 Å to about 1,500 Å is formed on passivation layer 200. A layer of photoresist is patterned over dielectric layer 208 to form a masking structure 210 having masking elements 212 and openings 214 that expose portions of dielectric layer 208 over contacts 190 and 192. The portions of dielectric layer 208 exposed by openings 214 and the portions of passivation layer 200 under the portions of dielectric layer 208 exposed by openings 214 are removed using, for example, a wet etch technique. Removing the exposed portions of dielectric layer 208 and the portions of passivation layer 200 under portions of dielectric layer 208 exposed by openings 214 exposes contacts 190 and 192.
Referring now to FIG. 17, masking elements 212 are removed and a photosensitive polyimide layer 220 having a post-cure thickness of at least about 8 micrometers (μm) is formed over dielectric layer 208 and the exposed portions of contacts 190 and 192. By way of example, polyimide layer 220 is dispensed to have a thickness of about 16 μm and then spin coated to have a substantially planar surface and a post-cure thickness of about 10 μm. Suitable photosensitive polyimide materials include photosensitive polyimide sold under the trademark PIMEL from Asahi, HDM polymeric coatings from Hitachi Chemical and DuPont Electronics, polybenzoxazole (PBO), bisbenzocyclbutene (BCB), or the like. It should be noted that layer 200 is not limited to being a photosensitive polyimide but may be a non-photosensitive material that is patterned using photoresist.
Referring now to FIG. 18, portions of polyimide layer 220 above the portions of electrodes 190 and 192 that were exposed through openings in dielectric layer 208 and passivation layer 200 are removed by exposure to electromagnetic radiation followed by a develop step. Polyimide layer 220 is cured after removal of the portions exposed to the electromagnetic radiation. Removal of the exposed portions of polyimide layer 220 re-exposes portions of electrodes 190 and 192 and a portion of dielectric layer 208 over conductor 198.
Still referring to FIG. 18, an adhesion layer 222 having a thickness ranging from about 1,500 Å to about 2,500 Å is formed on polyimide layer 220 and on the exposed portions of electrodes 190 and 192, and the exposed portion of dielectric material 208 over conductor 198. Suitable materials for adhesion layer 222 include titanium tungsten, titanium nitride, titanium, tungsten, platinum, or the like. A copper seed layer 224 having a thickness ranging from about 1,500 Å to about 5,000 Å is formed on adhesion layer 222. By way of example, layers 222 and 224 are each about 2,000 Å thick. A layer of photoresist is formed on copper seed layer 224 and patterned to form a masking structure 228 having masking elements 230 and openings 232. Preferably, the thickness of the photoresist layer is selected to be thicker than the copper to be plated in a subsequent step. By way of example, the thickness of the photoresist layer is about 14 nm.
Briefly referring to FIG. 19, a mask 228 having a masking pattern 233 is illustrated for patterning the photoresist layer. Light passes through the dark regions to expose portions of the photoresist layer. The portions of the photoresist layer exposed to light are removed, leaving masking elements 230 and exposing portions of copper seed layer 224.
Referring now to FIG. 20, copper is plated onto the exposed portions of copper seed layer 224 forming a contact structure 234, a contact structure 236, a plate 238 of MIM capacitor 239, and windings 240 of a coil or indictor 242.
Referring now to FIG. 21, masking elements 230 are removed to expose portions of copper seed layer 224 that were protected by masking elements 230. The exposed portions of copper seed layer 234 are removed exposing portions of adhesive layer 222, which are also removed to expose portions of polyimide layer 220. By way of example the portions of copper seed layer 224 and adhesion layer 222 are removed using a wet etch technique.
A layer of photosensitive material 246 having a thickness of at least about 8 μm is formed on the exposed portions of polyimide layer 220, the exposed portions of contact structures 234 and 236, MIM capacitor 239, and on windings 240. By way of example, polyimide layer 246 is dispensed to have a thickness of about 16 μm and then spin coated to have a substantially planar surface and a post-cure thickness of about 10 μm. It should be noted that the thickness of polyimide layer 246 is selected to reduce parasitics, e.g., parasitic capacitances, between windings, contact structures 234 and 236, and windings 240, and a copper layer to be plated above polyimide layer 246. Suitable photosensitive polyimide materials have been described with reference to polyimide layer 220.
Referring now to FIG. 22, portions of polyimide layer 246 above the portions of contact structures 234 and 236 are removed by exposure to electromagnetic radiation followed by a develop step. Polyimide layer 246 is cured after removal of the portions exposed to the electromagnetic radiation. Removal of the exposed portions of polyimide layer 246 exposes portions of contact structures 234 and 236. An adhesion layer 248 having a thickness ranging from about 1,500 Å to about 2,500 Å is formed on polyimide layer 246 and on the exposed portions of contact structures 234 and 236. Suitable materials for adhesion layer 248 include titanium tungsten, titanium nitride, titanium, tungsten, platinum, or the like. A copper seed layer 250 having a thickness ranging from about 1,500 Å to about 5,000 Å is formed on adhesion layer 248. A layer of photoresist is formed on copper seed layer 250. Preferably, the thickness of the photoresist layer is selected to be greater than the thickness of a copper layer to be plated on copper seed layer 250. The thickness of the photoresist layer may range from about 5 μm to about 20 μm and may be, for example, about 14 μm. The photoresist layer is patterned to form masking elements 252 having openings 254 that expose portions of copper seed layer 250. As those skilled in the art will appreciate, the thickness of photoresist layer 216 may be process limited because of line width definition limitations.
Briefly referring to FIG. 23, a mask 256 having a masking pattern 258 is illustrated for the patterning photoresist layer. Light passes through the dark regions to expose portions of the photoresist layer. The portions of the photoresist layer exposed to light are removed, forming masking elements 252 and openings, which openings expose portions of copper seed layer 250.
Referring again to FIG. 22, copper is plated onto the exposed portions of copper seed layer 250 forming a contact structure 260, a contact structure 262, and windings 264 of a coil or inductor 259.
Referring now to FIG. 24, masking elements 252 are removed to expose portions of copper seed layer 250 that were protected by masking elements 252. The exposed portions of copper seed layer 250 are removed exposing portions of adhesive layer 248, which are also removed to expose portions of polyimide layer 246. By way of example the portions of copper seed layer 250 and adhesion layer 248 are removed using a wet etch technique.
A polyimide layer 268 having a post-cure thickness of at least about 8 μm is formed on the exposed portions of polyimide layer 246, the exposed portions of contact structures 260 and 262, and on windings 264. By way of example, polyimide layer 268 is dispensed to have a thickness of about 16 μm and then spin coated to have a substantially planar surface and a post-cure thickness of about 10 μm. Suitable photosensitive polyimide materials have been described with reference to polyimide layer 220. Like layer 220, layer 246 is not limited to being a photosensitive polyimide but may be a non-photosensitive material that is patterned using photoresist.
The portions of polyimide layer 268 above contact structures 260 and 262 are exposed to electromagnetic radiation, developed and removed to expose contact structures 260 and 262.
FIG. 25 is a circuit diagram of a semiconductor component 300 that includes a common mode filter 302 monolithically integrated with a protection device 14. What is shown in FIG. 25 are a inductors 306 and 308 and capacitors 310 and 312. Inductor 306 has an input terminal connected to a terminal of capacitor 310 and an output terminal connected to the other terminal of capacitor 310 and inductor 308 has an input terminal connected to a terminal of capacitor 312 and an output terminal connected to the other terminal of capacitor 312. In accordance with an embodiment, protection device 14 includes a diode 30 having a cathode connected to the input terminal of inductor 306 and an anode connected to the anode of a diode 32. The cathode of diode 32 is connected to the input terminal of inductor 308. The commonly connected anodes of diode 30 and 32 may be connected to receive a source of potential such as, for example ground.
FIG. 26 is a circuit diagram of a semiconductor component 320 that includes a common mode filter 302A monolithically integrated with a protection device 14. What is shown in FIG. 26 are inductors 306 and 308 connected to protection device 14. In accordance with an embodiment, protection device 14 includes a diode 30 having a cathode connected to the input terminal of inductor 306 and an anode connected to the anode of a diode 32. The cathode of diode 32 is connected to the input terminal of filter 308. The commonly connected anodes of diode 30 and 32 may be connected to receive a source of potential such as, for example ground.
FIG. 27 is a circuit diagram of a semiconductor component 350 that includes a common mode filter 302 monolithically integrated with a protection device 14A. What is shown in FIG. 27 are inductors 306 and 308 and capacitors 310 and 312, which have been described with reference to FIG. 25. Inductor 306 has an input terminal connected to a terminal of capacitor 310 and an output terminal connected to the other terminal of capacitor 310 and inductor 308 has an input terminal connected to a terminal of capacitor 312 and an output terminal connected to the other terminal of capacitor 312.
In accordance with an embodiment, protection device 14A comprises single channel ESD structures 40 and 42. ESD structure 40 comprises diodes 44 and 46 and an npn bipolar transistor 48 and ESD structure 42 comprises diodes 50 and 52 and an npn bipolar transistor 54. Diode 44 has an anode commonly connected to the cathode of diode 46 and to the non-inverting input of common mode filter 350. The collector of npn bipolar transistor 48 is connected to the cathode of diode 44 and the emitter of npn bipolar transistor 48 is connected to the anodes of diode 46 and 50. Diode 52 has an anode commonly connected to the cathode of diode 50 and to the non-inverting input of common mode filter 350. The collector of npn bipolar transistor 54 is connected to the cathode of diode 52 and the emitter of npn bipolar transistor 54 is connected to the anodes of diodes 46 and 50.
FIG. 28 is a circuit diagram of a semiconductor component 360 that includes a common mode filter 302A monolithically integrated with a protection device 14A. What is shown in FIG. 26 are inductors 306 and 308 connected to protection device 14A. It should be noted that common mode filter 302A differs from common mode filter 302 in that capacitors 310 and 312 are absent from common mode filter 302A.
FIG. 29 is a layout 370 of coil filters such as, for example, coils 306 and 308. Coils 306 and 308 are manufactured over a semiconductor material having a central portion and a peripheral portion. Coil 306 is formed in a sub-portion of the central portion and coil 308 is formed in another sub-portion of the central portion. It should be noted that coils 306 and 308 are configured to be vertically positioned with respect to each other and vertically spaced apart by a dielectric material.
FIG. 30 is a plot 364 of the common mode performance and differential mode performance of a semiconductor component in accordance with embodiments of the present invention. Plot 364 includes a trace 366 of the common mode gain versus frequency response and a trace 368 of the differential mode gain versus frequency response. Trace 366 includes notches 372 and 374.
FIG. 31 is a plot 376 of ESD clamping performance of a semiconductor component in accordance with embodiments of the present invention in which an ESD event is in the positive direction.
FIG. 32 is a plot 378 of ESD clamping performance of a semiconductor component in accordance with embodiments of the present invention in which an ESD event is in the negative direction.
Although certain preferred embodiments and methods have been disclosed herein, it will be apparent from the foregoing disclosure to those skilled in the art that variations and modifications of such embodiments and methods may be made without departing from the spirit and scope of the invention. It is intended that the invention shall be limited only to the extent required by the appended claims and the rules and principles of applicable law.

Claims

What is claimed is:

1. A semiconductor component, comprising a common mode filter monolithically integrated with a protection device, the common mode filter comprising:

a first coil having first and second terminals;

a second coil having first and second terminals, the first terminal of the second coil coupled to the second terminal of the first coil, the first coil magnetically coupled to the second coil;

a third coil having first and second terminals;

a fourth coil having first and second terminals, the first terminal of the fourth coil coupled to the second terminal of the third coil, the third coil magnetically coupled to the fourth coil;

the protection device having a first terminal coupled to the first terminal of the first coil and a second terminal coupled to the first terminal of the third coil; and

a first energy storage element having first and second terminals, the first terminal of the first energy storage element coupled to the second and first terminals of the first and second coils, respectively.

2. The semiconductor component of claim 1, further including a second energy storage element having first and second terminals, the first terminal of the second energy storage element coupled to the second and first terminals of the third and fourth coils, respectively, and the second terminals of the first and second energy storage elements coupled together.

3. The semiconductor component of claim 2, wherein the first and second energy storage elements are metal-insulator-metal capacitors.

4. The semiconductor component of claim 2, further including a fifth coil, the fifth coil having first and second terminals, the first terminal coupled to the second terminals of the first and second energy storage elements.

5. The semiconductor component of claim 4, further including a third energy storage element having a first terminal coupled to the first terminal of the fifth coil and a second terminal coupled to the second terminal of the fifth coil.

6. The semiconductor component of claim 1, wherein the protection device comprises:

a first diode having an anode and a cathode, the cathode coupled to the first terminal of the first coil;

a second diode having an anode and a cathode, the anodes of the first and second diodes coupled together and the cathode of the second diode coupled to the first terminal of the third coil.

7. The semiconductor component of claim 1, wherein the protection device comprises:

a first diode having an anode and a cathode; and

a second diode having an anode and a cathode, the cathode of the first diode coupled to the first terminal of the first coil, the cathode of the second diode coupled to the anode of the first diode and the anode of the second diode coupled to the first terminal of the third coil.

8. The semiconductor component of claim 7, further including a transistor having a control electrode and first and second current carrying electrodes, the first current carrying electrode coupled to the cathode of the first diode and the second current carrying electrode coupled to the anode of the second diode.

9. A method for manufacturing a semiconductor component having a common mode filter monolithically integrated with a protection device, comprising:

providing a semiconductor material having a major surface and a resistivity of at least 10 ohm-centimeters;

forming a plurality of trenches in the semiconductor material;

forming the protection device from the semiconductor material between first and second trenches of the plurality of trenches;

monolithically integrating a common mode filter with the protection device; and

monolithically integrating a metal-insulator-metal capacitor with the common mode filter.

10. The method of claim 9, wherein providing the semiconductor material comprises:

providing a semiconductor substrate having a resistivity of at least 5 ohm-centimeters;

forming a first epitaxial layer of a first conductivity type over the semiconductor substrate; and

forming a second epitaxial layer of a second conductivity type over the first epitaxial layer.

11. The method of claim 10, further including forming a buried layer of the first conductivity type from portions of the first and second epitaxial layers.

12. The method of claim 11, wherein forming the plurality of trenches includes forming at least first, second, third, and fourth trenches, wherein a portion of the semiconductor material between the first and second trenches serves as a first device region, a portion of the semiconductor material between the second and third trenches serves as a second device region, and a portion of the semiconductor material between the third and fourth trenches serves as a third device region.

13. The method of claim 12, further including forming a first diode from the first device region, a second diode from the second device region, and a transistor from the third device region.

14. The method of claim 12, further including:

forming a first and second dopant regions of the second conductivity type in the third device region;

forming third and fourth dopant regions of the second conductivity type in the first and second dopant regions and fifth and sixth dopant regions of the second conductivity type in the first and second device regions, respectively; and

forming seventh and eighth dopant regions of the first conductivity type in the first and second device regions, respectively.

15. The method of claim 12, further including:

forming a first dielectric layer over the semiconductor material, the first dielectric layer configured to magnetically decouple the common mode filter from the protection structure;

forming a first coil of the common mode filter over the first dielectric layer;

forming a second dielectric layer over the first coil and the first dielectric layer; and

forming a second coil over the second dielectric layer, the second dielectric layer configured to magnetically coupled the first coil and the second coil.

16. The method of claim 15, further including forming a third layer of dielectric material over the second coil and the second layer of dielectric material.

17. The method of claim 16, wherein the first, second, and third layers of dielectric material are photosensitive polyimides.

18. The method of claim 12, wherein monolithically integrating the metal-insulator-metal capacitor comprises:

forming a first layer of dielectric material over the semiconductor material;

forming a first layer of electrically conductive material over the first layer of dielectric material;

forming a second layer of dielectric material over first layer of electrically conductive material; and

forming a second layer of electrically conductive material over the second layer of dielectric material.

19. A semiconductor component that includes a common mode filter monolithically integrated with a protection device, the semiconductor component comprising:

a semiconductor material having a peripheral region, a central region, and a resistivity of at least 5 ohm-centimeters, wherein the central region comprises a plurality of device regions isolated by isolation trenches;

a first coil over a first portion of the central region;

a second coil over a second portion of the central region;

a first insulating material over the first and second coils;

a third coil over the first portion of the central region;

a fourth coil over the second portion of the central region, the first insulating material between the first and third coils and the second and fourth coils;

a fifth coil over the peripheral region;

a protection device monolithically integrated with the first, second, third, fourth, and fifth coils, the protection device having a first terminal coupled to the first coil and a second terminal coupled to the second coil; and

a first metal-insulator-metal capacitor monolithically integrated with the protection device and over the first portion of the central region.

20. The semiconductor component of claim 19, further including a second metal-insulator-metal capacitor over the second portion of the central region, wherein the first metal-insulator-metal capacitor is laterally surrounded by the first coil and the second metal-insulator-metal capacitor is laterally surrounded by the second coil.